EP 2343877 A1 20110713 - IMAGE ENCRYPTION DEVICE/DECRYPTION DEVICE, IMAGE ENCRYPTION METHOD/DECRYPTION METHOD, AND IMAGE ENCRYPTION PROGRAM/DECRYPTION PROGRAM
Title (en)
IMAGE ENCRYPTION DEVICE/DECRYPTION DEVICE, IMAGE ENCRYPTION METHOD/DECRYPTION METHOD, AND IMAGE ENCRYPTION PROGRAM/DECRYPTION PROGRAM
Title (de)
EINRICHTUNG, VERFAHREN UND PROGRAMM ZUR BILDVERSCHLÜSSELUNG/-ENTSCHLÜSSELUNG
Title (fr)
DISPOSITIF DE CHIFFREMENT/DISPOSITIF DE DÉCHIFFREMENT D'IMAGE, PROCÉDÉ DE CHIFFREMENT/PROCÉDÉ DE DÉCHIFFREMENT D'IMAGE ET PROGRAMME DE CHIFFREMENT/PROGRAMME DE DÉCHIFFREMENT D'IMAGE
Publication
Application
Priority
JP 2008003012 W 20081023
Abstract (en)
In the encryption processes, some constraints are imposed on the size of an encryption field. For example, when the numbers of divided blocks in the height and width dimensions are respectively divided by a preset positive integer, the size of an encryption field is restricted such that the remainder will be 0 (i.e., the numbers of divided blocks are multiples of positive integers preset for the respective height and width) or a number equal to or larger than 1. In the decryption processes that correspond to the encryption processes above, the block positions in the encryption field are detected according to the constraint on the number of blocks of the encrypted image. As the numbers of blocks are restricted in advance in the height and width dimensions at the time of performing encryption, the numbers of blocks that need to be taken into consideration can be reduced at the time of detecting the block positions. As a result, the precision of decryption improves.
IPC 8 full level
H04N 1/387 (2006.01); G09C 1/00 (2006.01); G09C 1/04 (2006.01); G09C 5/00 (2006.01); H04N 1/44 (2006.01)
CPC (source: EP US)
G09C 1/04 (2013.01 - EP US); H04N 1/448 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
Designated extension state (EPC)
AL BA MK RS
DOCDB simple family (publication)
EP 2343877 A1 20110713; EP 2343877 A4 20120328; JP 5077439 B2 20121121; JP WO2010046951 A1 20120315; US 2011280395 A1 20111117; WO 2010046951 A1 20100429
DOCDB simple family (application)
EP 08877517 A 20081023; JP 2008003012 W 20081023; JP 2010534605 A 20081023; US 201113088742 A 20110418